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Université de Neuchâtel

Colour polymorphism in the leaf beetle genus 'Oreina'

Van Noort, Tom ; Benrey, Betty (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2013.

This dissertation investigates the maintenance of colour polymorphism in the leaf beetle genus Oreina CHEVROLAT (Coleoptera; Chrysomelidae). The remarkable colour variation in this seemingly aposematic and chemically defended genus forms a paradox with current scientific views concerning predator learning and mimicry. Using a variety of approaches we explore the selective forces that...

Université de Neuchâtel

Comparative susceptibility of larval instars and pupae of the western corn rootworm to infection by three entomopathogenic nematodes

Kurtz, B. ; Hiltpold, Ivan ; Turlings, Ted C. J. ; Kuhlmann, Ulrich ; Toepfer, Stefan

In: BioControl, 2009, vol. 54, no. 2, p. 255-262

As a first step towards the development of an ecologically rational control strategy against western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) in Europe, we compared the susceptibility of the soil living larvae and pupae of this maize pest to infection by three entomopathogenic nematode (EPN) species. In laboratory assays using sand-filled...

Université de Neuchâtel

Production of cardenolides in different life stages of the chrysomelid beetle Oreina gloriosa

Eggenberger, F. ; Rowell-Rahier, Martine

In: Journal of Insect Physiology, 1993, vol. 39, no. 9, p. 751-759

Cardenolide production in larval, pupal, and adult leaf beetles Oreina gloriosa (Coleoptera: Chrysomelidae) is compared. Significantly different levels of cardenolides were found in the various developmental stages of this species: early and late fourth-instar larvae (14 and 19 nmol, respectively), pupae (10 nmol), 1-day-old imagos (8 nmol). The developmental effects on individual...

Université de Neuchâtel

Biochemical strategy of sequestration of pyrrolizidine alkaloids by adults and larvae of chrysomelid leaf beetles

Hartmann, Thomas ; Theuring, Claudine ; Schmidt, Jürgen ; Rahier, Martine ; Pasteels, Jacques M.

In: Journal of Insect Physiology, 1999, vol. 45, no. 12, p. 1085-1095

Tracer feeding experiments with 14C-labeled senecionine and senecionine N-oxide were carried out to identify the biochemical mechanisms of pyrrolizidine alkaloid sequestration in the alkaloid-adapted leaf beetle Oreina cacaliae (Chrysomelidae). The taxonomically closely related mint beetle (Chrysolina coerulans) which in its life history never faces pyrrolizidine...

Université de Neuchâtel

Selective sequestration and metabolism of plant derived pyrrolizidine alkaloids by chrysomelid leaf beetles

Hartmann, Thomas ; Witte, Ludger ; Ehmke, Adelheid ; Theuring, Claudine ; Rowell-Rahier, Martine ; Pasteels, Jacques M.

In: Phytochemistry, 1997, vol. 45, no. 3, p. 489-497

Pyrrolizidine alkaloids (PAs) are assumed to function as plant defence compounds against herbivory. A number of adapted insects are known to sequester plant derived PAs for their own benefit. Here we summarize the chemical interactions between leaf beetles of the genus Oreina (Coleoptera, Chrysomelidae) and their host plants Adenostyles spp., Senecio nemorensis, and S....

Université de Neuchâtel

Chemical defence in chrysomelid eggs and neonate larvae

Pasteels, Jacques M. ; Daloze, D. ; Rowell-Rahier, Martine

In: Physiological Entomology, 1986, vol. 11, no. 1, p. 29-37

Eggs and neonate larvae of chrysomelid beetles (sub-tribes Chrysomelina and Phyllodectina) were investigated for the presence of defensive substances. The two isoxazolinone glucosides (compounds 1 and 2), characteristic of the adult defence secretion, were detected in the eggs of all studied species. Compound 2, containing a nitropropionate, is always present in concentrations (above...